Leica DM R Serie Mode D'emploi page 43

The tube factor is only engraved on the
microscope if it is not 1x. The HC P (Pol) tube
system has 2 switchable tube lenses, 1x and
1.6x, whereas HC V tube optics have 3 switchable
tube lenses. The Leica DM RD HC phototube
allows a continuous variation of the tube factor.
Useful magnification
The total magnification for visual observation
should not be more than 1000x the objective
aperture. In the above example (n.a. = 0.50) this
would be the case for a total magnification of
about 500x using tube factor 2x.
When this threshold value is exceeded, e.g. with
100x/1.30 Oil objective, 10x eyepiece and tube
factor 1.6x the image may appear out of focus
(empty magnification).
/20, /22, /25
Field number (fov) of the eyepiece. The field
number represents the diameter (in mm) of the
intermediate image that can be viewed through
the eyepiece. This appears magnified by the
eyepiece factor. The microscope image in a 10x/
20 eyepiece therefore appears to be as large as
a circle of 200 mm diameter, observed from a
distance of 250 mm (250 mm = reference viewing
distance).
The field number of the eyepieces used must
correspond with the field performance of the
objectives. If the eyepieces have too high a field
performance for the field flattening of the
objective, part of the field of view, e.g. the edge,
may appear out of focus.
Objectiv series
Achromats
C PLAN Achromats
N PLAN Planachromats
HC PL FLUOTAR ® Semiapo.
HC PL APO Planapochromats
Object field diameter: If you divide the eyepiece
field of view by the objective magnification, you
will get the real diameter of the observed object
field. The eyepiece magnification is not part of
the calculation. For example, with the 10x/25
eyepiece and a 50 objective an object field of
25 : 50 = 0.5 mm can be viewed.
+) Fov 28 at zoom factor 0.9 with photo system DM RD HC
max. recommended
eyepiece field od fiew
15 20 22 25 28
+)
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